APNIC eLearning: IPv6 Addressing and Subnetting

1 APNIC elearning : ipv6 Addressing and Subnetting Contact: Overview ipv6 Address Text Representation ipv6 Addressing Structure ipv6 Address Management Hierarchy Local Addresses Global Addresses Interface ID ipv6 Autoconfiguration Subnetting ipv6 Addressing An ipv6 address is 128 bits long So the number of addresses are 2^128 = 340282366920938463463374607431768211455 In hex, 4 bits (also called a nibble ) is represented by a hex digit So 128 bits is reduced down to 32 hex digits 2001:0DB8:D35D:B33F::/64 2001:DC0:A910.

2 1010 1001 0001 0000 nibbles ipv6 Addressing Hexadecimal values of eight 16 bit fields X:X:X:X:X:X:X:X (X=16 bit number, ex: A2FE) 16 bit number is converted to a 4 digit hexadecimal number Example: FE38:DCE3:124C:C1A2:BA03:6735:EF1C:683D Abbreviated form of address 4 EED:0023:0000:0000:0000:036E:1250:2B00 4 EED:23:0:0:0:36E:1250:2B00 4 EED:23::36E:1250:2B00 (Null value can be used only once) Groups of zeroes Leading zeroes Double colons ipv6 Addressing 2001:0DB8:DEAD:BEEF:1AB6:503F:A804:71D9 0010 0000 0000 0001 0000 1101 1011 1000 1101 1110 1010 1101 1011 1110 1110 1111 0001 1010 1011 0110 1001 0000 0011 1111 1010 1000 0000 0100 0111 0001 1101 1001 ipv6 Addressing structure 1 128 ISP /32 32 128 bits Customer Site /48 16 End Site Subnet /64 16 64 Device 128 Bit Address Interface ID 65 Network Prefix 64 ipv6 Address Management Hierarchy ipv6 Addressing model RFC 4291 Unicast Packet is sent to a single interface Anycast Packet is sent to the nearest of group interfaces (in terms of routing)

3 Distance) Multicast Packet is sent to multiple interfaces Addresses Without a Network Prefix Loopback ::1/128 Unspecified Address ::/128 IPv4-mapped ipv6 address ::ffff/96 [ ] IPv4-compatible ipv6 address ::/96 [ ] ipv6 Address Range Unspecified Address ::/128 Loopback ::1/128 Global Unicast (0010) 2000::/3 Link Local (1111 1110 10) FE80::/10 Multicast Address (1111 1111) FF00::/8 Unique Local Address FC00::/7 Local Addresses With Network Prefix Link Local Address A special address used to communicate within the local link of an interface anyone on the link as host or router This address in packet destination that packet would never pass through a router fe80.

4 /10 Local Addresses With Network Prefix Unique Local ipv6 Unicast Address Addresses similar to the RFC 1918 / private address like in IPv4 but will ensure uniqueness A part of the prefix (40 bits) are generated using a pseudo-random algorithm and it's improbable that two generated ones are equal fc00::/7 Example webtools to generate ULA prefix Global Addresses With Network Prefix ipv6 Global Unicast Address Global Unicast Range: 0010 2000::/3 0011 3 FFF:FFFF:.. :/3 All five RIRs are given a /12 from the /3 to further distribute within the RIR region APNIC 2400:0000::/12 ARIN 2600:0000::/12 AfriNIC 2C00:0000::/12 LACNIC 2800:0000::/12 Ripe NCC 2A00:0000::/12 6to4 Addresses 2002.

5 /16 Designed for a special tunneling mechanism [RFC 3056] to connect ipv6 Domains via IPv4 Clouds Need 6to4 relay routers in ISP network Examples and Documentation Prefix Two address ranges are reserved for examples and documentation purpose by RFC 3849 For examples, use 3fff:ffff::/32 For documentation, use 2001:0DB8::/32 Interface ID The lowest-order 64-bit field addresses May be assigned in several different ways: auto-configured from a 48-bit MAC address expanded into a 64-bit EUI-64 assigned via DHCP manually configured auto-generated pseudo-random number possibly other methods in the future EUI-64 0 0 2 6 B 0 E 5 8 3 3 C 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 6 B 0 E 5 8 3 3 C F F F E 0 2 2 6 B 0 E 5 8 3 3 C F F Mac Address EUI-64 Address Interface Identifier U/L bit F E Zone IDs for Local-use Addresses In Windows XP for example.

6 Host A: fe80::2abc:d0ff:fee9:4121%4 Host B: fe80::3123:e0ff:fe12:3001%3 Ping from Host A to Host B ping fe80::3123:e0ff:fe12:3001%4 (not %3) Identifies the interface zone ID on the host which is connected to that segment. ipv6 Autoconfiguration RFC 2462 Stateless mechanism For a site not concerned with the exact addresses No manual configuration required Minimal configuration of routers No additional servers Stateful mechanism For a site that requires tighter control over exact address assignments Needs a DHCP server DHCPv6 ipv6 Autoconfiguration Tentative address (link-local address) Well-known link local prefix +Interface ID (EUI-64) Ex: FE80::310:BAFF:FE64:1D Is this address unique?

7 1. A new host is turned on. 2. Tentative address will be assigned to the new host. 3. Duplicate Address Detection (DAD) is performed. First the host transmit a Neighbor Solicitation (NS) message to the solicited node multicast address (FF02::1:FF64:1D) corresponding to its to be used address 5. If no Neighbor Advertisement (NA) message comes back then the address is unique. 6. FE80::310:BAFF:FE64:1D will be assigned to the new host. Assign FE80::310:BAFF:FE64:1D 2001:1234:1:1/64 network ipv6 Autoconfiguration FE80::310:BAFF:FE64:1D Send me Router Advertisement 1.

8 The new host will send Router Solicitation (RS) request to the all-routers multicast group (FF02::2). 2. The router will reply Routing Advertisement (RA). 3. The new host will learn the network prefix. , 2001:1234:1:1::/64 4. The new host will assigned a new address Network prefix+Interface ID , 2001:1234:1:1:310:BAFF:FE64:1D Router Advertisement Assign 2001:1234:1:1:310:BAFF:FE64:1D 2001:1234:1:1/64 network Subnetting (Example) Provider A has been allocated an ipv6 block 2001:DB8::/32 Provider A will delegate /48 blocks to its customers Find the blocks provided to the first 4 customers Subnetting (Example) 2001:0DB8::/32 2001:0DB8:0000:/48 Original block: Rewrite as a /48 block: This is your network prefix!

9 How many /48 blocks are there in a /32? /32/48=2128 322128 48=296280=216 Find only the first 4 /48 Subnetting (Example) 2001:0DB8:0000::/48 In bits 0000 0000 0000 0000 2001:0DB8: ::/48 0000 0000 0000 0001 2001:0DB8: ::/48 0000 0000 0000 0010 2001:0DB8: ::/48 0000 0000 0000 0011 2001:0DB8: ::/48 Start by manipulating the LSB of your network prefix write in BITS 2001:0DB8:0000::/48 2001:0DB8:0001::/48 2001:0DB8:0002::/48 2001:0DB8:0003::/48 Then write back into hex digits Appendix: ipv6 Addressing Exercise Exercise : ipv6 Subnetting 1.

10 Identify the first four /36 address blocks out of 2406:6400::/32 1. _____ 2. _____ 3. _____ 4. _____ Exercise : ipv6 Subnetting 1. Identify the first four /35 address blocks out of 2406:6400::/32 1. _____ 2. _____ 3. _____ 4. _____ Questions Please remember to fill out the feedback form <survey-link> Slide handouts will be available after you fill out the survey ipv6 @ APNIC APNIC Helpdesk Chat Thank You! End of Session